Microprocessor, system for controlling a device and apparatus

ABSTRACT

A microprocessor may include a logic circuit for executing instructions of a data processing application. The microprocessor may have a timer system which includes a clock counter connected to a clock input for receiving a clock signal and counting a number of cycles of the clock signal. A clock comparator may be connected the clock counter and to a timer register in which a timer reference value can be stored. The clock comparator may compare a number of cycles of the clock signal with the timer reference value and generate a timer signal based on the comparison. The timer system may have a timer output for outputting timer signal. The timer system may include a control input for receiving a digital value representing a measured value of a sensed parameter of a device and a control register in which a control reference value can be stored. A control comparator may be connected the control input. The control comparator may compare the digital value with the reference value and generating a device control signal based on the comparison. The timer system may have a control output for outputting the device control signal to an actuator arranged to control the parameter of the device.

FIELD OF THE INVENTION

This invention relates to a microprocessor, to a control system and toan apparatus including a control system.

BACKGROUND OF THE INVENTION

Many hard real-time control systems require the precise control ofactuators to control a process or plant or machinery. These actuatorsmust be accurately managed, for example to turn on and off at criticaltimes or angles of rotating machines or at specific voltages orcurrents.

Control systems are known in which an analog application specificintegrated circuit is used, which generally provide a fast, andtherefore more accurate control loop, those control systems areexpensive and inflexible because they cannot be reconfigured to performanother function in another application.

From U.S. Pat. No. 5,233,573, a microcontroller is known whichincorporates a digital timer apparatus and a central processing unit(CPU). The digital timer apparatus receives an external signal. Upon atransition of the external signal, the value of a free-running counterdriven by a constant frequency clock signal, is loaded into a captureregister and causes a pulse accumulator to be incremented. The pulseaccumulator is reset periodically by an interval timer. Thus, both thetime of a transition and the number of transitions during a certainperiod of time can be determined. The time of a transition and thenumber of transitions are used by the CPU to perform a control function.

However, a disadvantage of this prior art system is that, although a CPUis flexible and can be relatively cheap, the CPU is relatively slowwhich makes the control slow and imprecise.

SUMMARY OF THE INVENTION

The present invention provides a microprocessor, a system forcontrolling a device and an apparatus as described in the accompanyingclaims.

Specific embodiments of the invention are set forth in the dependentclaims.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details, aspects and embodiments of the invention will bedescribed, by way of example only, with reference to the drawings.

FIG. 1 schematically shows a block diagram of an example of anembodiment of a microprocessor.

FIG. 2 schematically shows a block diagram of a fuel injection system.

FIG. 3 schematically shows a block diagram of an example of anembodiment of a system for controlling a device.

FIG. 4 schematically shows a flow chart of an example of a method forcontrolling an apparatus.

FIG. 5 schematically illustrates the timing of components of the exampleof FIG. 3

FIG. 6 schematically shows an example of an embodiment of an apparatusincluding a system for controlling a device in the apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, an example of a microprocessor 1 is shown therein.The microprocessor 1 may include one or more logic circuit(s) (LC) 2 andone or more timer systems 10. The microprocessor 1 may for example be ageneral purpose microprocessor. Alternatively, the microprocessor 1 maybe a microcontroller (μC), such as a controller for an electronicstability control (ESC) system used to modulate braking and tractionforces of a vehicle, such as a car, a control system for an engine. Themicroprocessor 1 may be implemented in any manner suitable for thespecific implementation. The microprocessor 1 may for example include,in addition to the logic circuit 2, an input/output interface (I/O) 5 orother components, such as communication interfaces and/or coprocessorsand/or analog-to-digital converters and/or clocks and reset generationunits and/or voltage regulators and/or memory 4 (such as for instanceflash, EEPROM, RAM) and/or error correction code logic and/or othersuitable components.

The components, such as the memory 4, the I/O 5 and the timer system 10may be connected to the logic circuit 2. In the example of FIG. 1, themicroprocessor 1 for example includes an internal bus 3 which connectsthe logic circuit 2 to other components in the microprocessor, such asto the memory 4, the I/O 5 and the timer system 10. In the example ofFIG. 1, the logic circuit 2 is connected with an interface 20 to aninput/output 30 of the internal bus 3. The memory 4 is connected with aninterface 40 to an input/output 31 of the internal bus 3. An interface50 of the I/O 5 is connected to the logic circuit 2 via the bus 3. Thetimer system 10 is connected with an interface 113 to an input/output 33of the internal bus 3 in the example of FIG. 1.

The microprocessor 1 may receive data from and/or output to the worldoutside the microprocessor. For instance, in FIG. 1 the I/O 5 isconnected to input/output contacts 51 of the microprocessor 1, forexample to input received from and/or output data to the world outsidethe microprocessor 1.

The logic circuit 2 may be implemented in any manner suitable for thespecific implementation. Although for sake of simplicity, only a singlelogic circuit 2 is shown in FIG. 1 the microprocessor 1 may include twoor more logic circuits, and for instance be a multi-core processor. Thelogic circuit 2 may for example be a central processing unit (CPU)and/or a coprocessor and/or a digital signal processor and/or anembedded processor.

The logic circuit 2 may, in operation, execute instructions of one ormore software applications. The software application may be any type ofapplication suitable for the specific implementation, and for example bea control application for controlling the operation of a physical deviceand for instance control a part of the vehicle, such as for example anengine or a fuel injection system of an engine.

The logic circuit 2 may for instance be a programmable circuit and maybe connected to one or more memories (MEM) 4, in which instructionsexecutable by the logic circuit 2 can be stored, for instance duringmanufacturing of the logic unit or after manufacturing.

The logic circuit 2 may for instance include one, or more, processorcores. The memory 4 may be connected to the processor core and theprocessor core may execute the instructions stored in the memory 4. Theprocessor core may for instance include the logic circuitry required toexecute program code in the form of machine code. The logic circuit 2may for instance include one or more of: an instruction decoder, anarithmetic unit, an address generation unit, and a load/store unit.

The timer system 10 may be implemented in any manner suitable for thespecific implementation. In the example shown in FIG. 1, the timersystem 10 is arranged to operate independent from the logic circuit 2and is communicatively connected to the logic circuit 2, e.g. via theinterfaces 20,113 and the internal bus 3.

As illustrated in FIG. 1, the timer system 10 may have one or more, inthis example two, clock counters 101-102 connected to one or more clockinputs 1010,1020 (in the example of FIG. 1, the clock inputs 1010, 1020are formed by the counter inputs). At the clock input 1010,1020, one ormore clock signals may be received. The clock counters 101-102 can counta number of cycles of the respective clock signal. As shown in FIG. 1,the clock counters 101-102 may be connected, via the clock inputs1010,1020 to a clock 100. For instance, as shown in the example, theclock 100 may be a source of a constant frequency clock signal and theclock counter(s) 101-102 may be up or down counters which output acounter value CNT1,CNT2 which increments or decrements with one unit perclock cycle.

The timer system 10 may include one or more clock comparators 105-106connected to the clock counter(s) 101,102. Each of the clock comparators105, 106 may also be connected to one or more timer registers 103,104 inwhich one or more timer reference values T1,T2 can be stored. In theexample of FIG. 1, a counter input 1051,1061 of the comparators 105,106is connected to a respective one of the clock counters 101,102 while therespective timer register 103,104 is connected to a reference input1050,1060 of a comparator 105,106. A comparator output 1052,1062 isconnected to a timer output 100 ₁,100 ₂ of the timer system 10.

The comparator 105,106 may compare the value presented at the counterinput 1051,1061, i.e. the counter value CNT1,CNT2 (and hence the countednumber of cycles of the clock signal CLCK), with the value presented atthe reference input 1050,1060, i.e. with the timer reference valueT1,T2. The comparator 105,106 may generate one or more timer signalsbased on the comparison and output the timer signal at a timer output100 ₁,100 ₂ of the timer system 10.

The clock comparator(s) 105,106 may for example output a binary signal(e.g. a binary zero) which has a first value during a period of time thecounter value CNT1,CNT2 is below the respective reference value T1,T2and a second value (e.g. a binary one) when the counter value CNT1,CNT2is higher than the reference value T1,T2. For example, the comparatormay operate as can be described with the pseudo code:

if CNT<T then timer signal=low else timer signal=high

However, the timer signals may also be of a different type and thecomparator may, for example, output a short pulse at the point in timethe counter value CNT1,CNT2 becomes equal to the reference value T1,T2.For example, the comparator may operate as can be described with thepseudo code:

if CNT==T then timer signal=high else if (CNT<T or CNT>T) timersignal=low

The comparator 105,106 may transmit the timer signal to a timer output100 ₁,100 ₂. In the example of FIG. 1, for instance, the timer signalpresented at a comparator output 1052,1062 can be outputted, via thetimer output 100 ₁,100 ₂ to which the respective comparator 105,106 isconnected, to the world outside the microprocessor 1. However, one ormore of the timer outputs 100 ₁,100 ₂ may, also or alternatively, beconnected to a component inside the microprocessor 1, such as to thelogic circuit 2, in order to provide timing information to therespective component for example.

As shown in FIG. 1, the timer system 10 may include one or more controlinputs 111,112. One or more of the control comparators 107,108 may beconnected the control input(s) 111,112. At the control inputs 111,112respective digital values s1,s2 may be presented. As explained below inmore detail, the digital values s1,s2 may represent the measured valuesof one or more sensed parameter of one or more devices 7.

The timer system 10 may include one or more control registers 109,110 inwhich one or more control reference values V1,V2 can be stored. Thecomparators 107,108 may compare the digital value s1,s2 with thereference value V1,V2 and generate one or more device control signalsbased on the comparison. The device control signals may then beoutputted at one or more control outputs 100 ₃,100 ₄, for example to anactuator 70 arranged to control the parameter of the device 7.

The control inputs 111,112 may, for example, be connected to a digitalvalue input 1071,1081 of the comparator 107,108 and the controlregisters 109,110 may, for example, be connected to a reference valueinput 1070,1080. The comparator 107,108 may compare the value presentedat the digital value input 1071,1081, with the value presented at thereference input 1070,1080 and hence compare the digital value s1,s2,with the reference value v1,v2. The comparator 107,108 may present thedevice control signals at a comparator output 1072,1082 which isconnected to a respective one of the control outputs 100 ₃,100 ₄ of thetimer system 10.

Thus, the microprocessor 1 can be used to provide a sensor-actuatorcontrol loop. Hence, a flexible and relatively cheap control system maybe obtained. The control system may for example be reconfigured bysimply adjusting the reference value v1,v2. Furthermore, because thecontrol signal is generated in the timer system, the control loop can befaster than a control loop which includes the logic circuit 2. Also, thecontrol system can be implemented few components, and may therefore beof a simple design.

The control outputs 100 ₃,100 ₄ may for example output the devicecontrol signal to the world outside the microprocessor 1, such as to adevice actuator 70 as is explained in more detail with reference to FIG.2. However, one or more of the control outputs 100 ₃,100 ₄ of the timersystem 10 may, also or alternatively, be connected to a component insidethe microprocessor 1, in order to provide information about the deviceto the respective component. The component inside the microprocessor 1may for example be the logic circuit 2.

The control comparator 107, 108 may be arranged to generate one or morefirst binary signals when the digital value s1,s2 is below the controlreference value v1,v2 and to generate one or more second binary signalsopposite to the first binary signal when the digital signal s1,s2exceeds the control reference value v1,v2. For example, the controlcomparator 107,108 may operate as can be described with the pseudo code:

if s<v, then control signal=low else control signal=high

The microprocessor may have any suitable number of control inputs,comparators and outputs. As illustrated in FIG. 1, the microprocessor 1may for example include two or more control inputs 111,112 for receivingrespective digital values. In the example of FIG. 1, each controlcomparator 107,108 is connected to a separate control input 111 resp.112 and hence is arranged to compare the digital value received at oneselected control input with the reference value. However, a controlcomparator 107,108 may also be connected to two or more control inputs111,112, for example via a time multiplexer and compare digital valuefrom two or more control inputs 111,112.

As shown in FIG. 1, the microprocessor 1 may include two or more controloutputs 100 ₃-100 ₄, each for outputting one or more respective controlsignals. For example, the control outputs 100 ₃-100 ₄ may be connectedtwo or more actuators for instance for actuating different parameters ofa device or for two or more different devices. However, themicroprocessor 1 may include a single control output, for instance incase only a single actuator is to be controlled.

As shown in FIG. 1, the microprocessor 1 may include ananalog-to-digital converter (ADC) 61. The ADC 61 may generate one ormore digital signals, such as binary signals or other discrete signals,representing one or more values of one or more parameter of an analogsignal, such as the amplitude of the analog signal.

The analog signal may for example be a sensor signal received from asensor 62 which senses a parameter of a device. The ADC 61 may forexample have an analog input 610 at which the analog signal may bereceived and which is connected to an output 621 of a sensor 62, whichtogether with the ADC 61 forms a digital sensor system 6. The sensor 62may for example have a sensing input 620 at which a physical inputstimulus (such as radiation, sound or other suitable stimulus) may bereceived. The sensor 62 may output a signal in response, such as anelectrical signal or other type of signal suitable to be inputted to theADC 61. It should be noted that in the example of FIG. 1, the ADC 61 isshown within the boundaries of the microprocessor 1. However, the ADC 61may be provided as a device separate from the device in which the logiccircuit 2 and the timer system 10 are provided, and for example beimplemented as an integrated circuit separate from, but connected to(and in the same package as) an integrated circuit in which the logiccircuit 2 and the timer system 10 are implemented. The ADC 61 may haveone or more digital outputs 611 at which the digital signal may bepresented. The digital output 611 may for example be connected to thecontrol input 111,112, and hence be inputted to the control comparator107,108 connected to the respective control input 111,112.

Hereinafter an electromagnetic fuel injection system is described by wayof an example of an apparatus including a control system. However, acontrol system may used to control other types of apparatus.

FIG. 2 schematically illustrates a configuration of a fuel injectionsystem 7 (hereinafter, referred to as an “electromagnetic fuel injectionsystem”) using an electromagnetic fuel injection pump that pressurizesand injects fuel by itself, as distinct from a conventional fuelinjection apparatus or fuel injection system that injects fuelpressurized and provided in/from a fuel pump or regulator.

As shown in FIG. 2, the electromagnetic fuel injection system mayinclude a plunger pump 72, which pressurizes and feeds fuel from a fueltank 71 into an inlet orifice nozzle 73. In the shown example, theplunger pump 72 is electromagnetically driven pump which comprises oneor more electromagnets 70 via which the operation of the pump 72 can becontrolled.

The inlet orifice nozzle 73 may, as shown, have an orifice portionthrough which the fuel is passed with a predetermined pressure. The fuelmay be fed into the orifice portion from the plunger pump 72. Aninjection nozzle 74 is positioned, in direction of the fuel flow,downstream of the inlet orifice nozzle 73. The injection nozzle 74 mayinject the fuel passed through the inlet orifice nozzle 73 with apressure higher than a predetermined value to an intake passage (e.g. ofan engine).

As shown, a microprocessor 1 may be arranged to control the operation ofthe plunger pump 72 and hence the operation of the fuel injectionsystem. The microprocessor 1 may for example output a control signal tothe plunger pump 72 based on one or more sensed operational parameterof, for instance, the engine or the coil. The sensed operationalparameter may for example include the amount current flowing through oneor more of the electromagnets 70 of the plunger pump 72. In the exampleof FIG. 2, for instance, a control input 111 of the microprocessor 1 isconnected to a electromagnet 70, via a line-up of an ADC 61 and a sensor62, in order to receive a digital value representing the amount ofcurrent flowing through the electromagnet 70. The timer system 10 in themicroprocessor 1 may compare the digital value with a reference valueand output a control signal based on the comparison. The control signalmay be outputted at the output 100 ₃ in order to control a parameter ofthe apparatus, i.e. in this example of the plunger pump 72. The controlsignal may control any suitable parameter and for example enable ordisable the current through the electromagnet 70 (and hence the magneticfield generated by the electromagnet 70).

Referring to FIG. 3, an example of a control system 7 is shown therein.In this example, the control system 7 is an on-off control system whichcontrols a magnetic coil 704. The coil 704 may for example be used asthe electromagnet in the example of FIG. 2 or in another system such asan ignition system (in which case the coil 704 may for example be aspark ignition coil) or an electric motor. However, it will be apparentthat the control system 7 may be implemented in any suitable manner andbe used to control other devices or parameters. In the example of FIG.3, a parameter of a device is controlled based on a sensed value of thesame parameter, and hence the control system 7 forms a sensor-actuatorfeedback system. However, it will be apparent that the sensed parameterof a device may also be used to control another parameter of that deviceor to control a parameter of another device.

In the example of FIG. 3, the magnetic coil 704 is connected with oneside to a voltage source Vb and with another side to ground GND. Acurrent can flow through the magnetic coil 704, from the voltage sourceVb to ground GND, and hence an magnetic field can be generated. In theshown example, switches 700-702 are provided which can enable or disablethe current through the magnetic coil and hence enable or disable themagnetic field, as explained below in more detail.

In the shown example the sensor 62 can detect the amount of current Iflowing through the magnetic coil 704. However, it will be apparent thatthe sensor 62 may in addition or alternatively sense another parameter.The sensor 62 includes in this example a current detecting resistor 703which is connects the low voltage side of the magnetic coil 704 toground GND. The resistor 703 connects the magnetic coil 704 to groundGND. Hence, when a magnetic field is generated, a current flows throughthe resistor 703 which is proportional to the current I flowing throughthe magnetic coil 704. The voltage difference between the coil side ofthe resistor 73 and ground GND is therefore proportional to the currentI flowing through the magnetic coil 704 and hence forms a measure forcurrent I. In the example, the resistor 73 forms the only path to groundfor the current through the magnetic coil and hence the voltagedifference is directly proportional to the current I. As shown in FIG.3, the coil side node of the resistor 703 is connected to the analoginput 610 of the ADC 61 and hence the voltage difference is inputted tothe ADC 61 as the analog signal.

In the example of FIG. 3, the sensing resistor 703 is connected to thelow voltage side of the magnetic coil 704 via a control switch 702. Inthis example, the sensing resistor, the control switch 702 and themagnetic coil 704 form a linear chain. Hence, the current through theresistor 703 is, except for leakage currents in the switch 702, the sameas the current through the magnetic coil 704 and the current flowingthrough the magnetic coil 704 can be controlled via the switch 702. Asshown, the control switch 702 is connected to the control output 100 ₃of the microprocessor 1. In this example, the control switch 702 is aField Effect Transistor (FET) connected with it's current terminals tothe magnetic coil 704 and to the resistor 703 respectively and connectedwith its control terminal (i.e. the gate) to the control output 100 ₃.By controlling the voltage Vg provided to the control terminal of theswitch 702, the current I flowing through the FET from the one currentterminal to the other current terminal can be controlled. For example, acurrent flow can be allowed or be blocked, and hence the coil can beswitched on or off.

Hence, the switch 702 forms an actuator which can actuate a parameter,in this example the current through the magnetic coil. The control inputof the switch 702 thus forms an actuator control input which isconnected to the control output 100 ₃ of the microprocessor 1.

The control system 7 may also include one or more actuators which arecontrolled based on the period of time instead of the sensed parameter.In the example of FIG. 3, for instance, the coil 704 is connected to apower supply V_(b) via a switch 701. The switch 701 can control thepower supplied to the coil 704. A boost switch 700 connects the nodebetween the switch 701 and the coil 704 to a boost supply V_(b), toaccelerate the transition of the switch 701 from open to closed (or viceversa). As shown, control terminal of the switches 700,701 are connectedto the clock outputs 100 ₁, 100 ₂ of the timer system 10. By controllingthe voltage Vg provided to the control terminal of the respective switch702, the current I flowing through the switch from the one currentterminal to the other current terminal can be controlled. For example, acurrent flow can be allowed or be blocked. Thus, the coil can beelectrically connected or electrically disconnected from the powersupply Vb.

Referring to FIGS. 4 and 5, the example shown in FIG. 3 may for exampleperform a process as follows. As illustrated in FIG. 4 with block 900,the process may be started by enabling the electrical connection betweenthe power supply Vb and the magnetic coil 704. For instance, theswitches 700,701 may be connected to the clock comparators 105-106.Thus, the power side switches 700,701 may be opened and closed accordingto a period of time set by the timer reference value T1,T2, asillustrated in FIG. 5. The timer reference values T1,T2 in the timerregisters 103,104 may be set such that the clock comparator(s) 105-106output a high signal which closes the switch 700,701 during a periodfrom the start (at T0) to an end T3, thus enabling operation of themagnetic coil during the period of time (shown from T0 to T3 in FIG. 5).

As illustrated in FIG. 4 with step 901, a parameter, e.g the voltageV_(R) over the resistor 703, may be sensed and as shown with step 902the sensed parameter may be compared with a reference value V_(TR)stored in the control register 109,110. When the voltage V_(R) exceedsthe reference value V_(TR), the current flow through the magnetic coil704 may be stopped, as e.g. shown at time T1 in FIG. 5. The current flowmay for example be stopped for a predetermined period of time T_(out),and then be switched on again, as indicated with step 904 in FIG. 4, forexample by opening and closing the switch 702, for example be applying asuitable voltage Vg at the control terminal, e.g. the gate, thereof, asshown in FIG. 5. As shown in FIG. 5, different reference values may beused at different points in time. For example, during a first period oftime (from T0 to T2 in FIG. 5) a first reference value (corresponding toa current I₁) may be set for the control reference value whereas duringa second period of time (from T2 to T3 in FIG. 5) a second referencevalue (corresponding to a current I₂) may be set.

Referring to FIG. 6, an example of an apparatus is shown therein. Theexample shown in FIG. 1, is a motorised vehicle, and more in particularis a car 8. The car 8 may include a microprocessor 1, which as shown mayfor example control braking systems 81 or a fuel injection system 7which can inject fuel into a combustion engine 84. As shown, themicroprocessor 1 may for example be connected to the braking systems 81,the fuel injection system 7 or other components such as a dashboardcontroller 82 via a suitable communication network 83, such as a FlexRaynetwork or other suitable system.

In the foregoing specification, the invention has been described withreference to specific examples of embodiments of the invention. It will,however, be evident that various modifications and changes may be madetherein without departing from the broader spirit and scope of theinvention as set forth in the appended claims. For example, the sensormay include any suitable type of sensor such as a current sensor, avoltage sensor, an angle sensor. Also, for example the sensor may be atemperature sensor, which is for example integrated on the die on whichthe microprocessor 1 is provided. When the sensed temperature exceeds atemperature threshold set in the control register, a suitable action maybe taken, such as the generation of an interrupt which is sent to thelogic circuit or switching the logic circuit to a lower power mode, inorder to limit further temperature rise.

Furthermore, the devices may be physically distributed over a number ofapparatuses, while functionally operating as a single device. Forexample, the components of the microprocessor 1 may be provided on twoor more dies which are contained into the same package. Also, devicesfunctionally forming separate devices may be integrated in a singlephysical device. For example, the switches 700-702 in the example ofFIG. 3 may be integrated in the microprocessor and be connected to acoil via suitable pins of the microprocessor.

However, other modifications, variations and alternatives are alsopossible. The specifications and drawings are, accordingly, to beregarded in an illustrative rather than in a restrictive sense.

In the claims, any reference signs placed between parentheses shall notbe construed as limiting the claim. The word ‘comprising’ does notexclude the presence of other elements or steps then those listed in aclaim. Furthermore, the words ‘a’ and ‘an’ shall not be construed aslimited to ‘only one’, but instead are used to mean ‘at least one’, anddo not exclude a plurality. The mere fact that certain measures arerecited in mutually different claims does not indicate that acombination of these measures cannot be used to advantage.

1. A microprocessor, comprising: a logic circuit for executinginstructions of a software application, and a timer system, said timersystem including: a clock input for receiving a clock signal; a clockcounter connected to said clock input for counting a number of cycles ofsaid clock signal; a clock comparator connected said clock counter andto a timer register in which a timer reference value can be stored, forcomparing a number of cycles of said clock signal with said timerreference value and generating a timer signal based on said comparison;and a timer output for outputting timer signal; a control input forreceiving a digital value representing a measured value of a sensedparameter of a device; a control register in which a control referencevalue can be stored; a control comparator connected said control input,for comparing said digital value with said reference value andgenerating a device control signal based on said comparison; and acontrol output for outputting said device control signal to an actuatorarranged to control said parameter of said device; an analog-to-digitalconverter (61) for generating a digital signal representing a value of aparameter of an analog signal, said parameter of said analog signalrepresenting said sensed parameter, said analog-to-digital converter(61) having an analog input (610) for receiving said analog signal and adigital output (611) for outputting said digital value, said digitaloutput (611) being connected to said control input (111,112).
 2. Amicroprocessor as claimed in claim 1, including at least two controlinputs for receiving respective digital values, and wherein said controlcomparator is arranged to compare at least one selected digital valuereceived at a selected control input with said reference value.
 3. Amicroprocessor as claimed in claim 1, including at least two controloutputs, each for outputting a respective control signal.
 4. Amicroprocessor as claimed in claim 1, wherein said control comparator isarranged to generate a first binary signal when said digital value isbelow said control reference value, and to generate a second binarysignal opposite to said first binary signal when said digital signalexceeds said control reference value.
 5. A system for controlling adevice, including: a sensor for sensing a parameter of said device; amicroprocessor as claimed in claim 1, said microprocessor beingconnected with a control input to said sensor.
 6. A system as claimed inclaim 5, further including an actuator for actuating said parameter ofsaid device, said actuator having an actuator control input connected tosaid control output of said microprocessor.
 7. A system as claimed inclaim 5, wherein said actuator includes one or more of: a fuel injector,8. A system as claimed in claim 5, wherein said sensor includes one ormore of: current sensor, voltage sensor, angle sensor.
 9. An apparatusincluding a system as claimed in claim
 5. 10. A system as claimed inclaim 6, wherein said actuator includes one or more of: a fuel injector,11. A system as claimed in claim 6, wherein said sensor includes one ormore of: current sensor, voltage sensor, angle sensor.
 12. A system asclaimed in claim 7, wherein said sensor includes one or more of: currentsensor, voltage sensor, angle sensor.
 13. A microprocessor as claimed inclaim 2, including at least two control outputs, each for outputting arespective control signal.
 14. A microprocessor as claimed in claim 2,wherein said control comparator is arranged to generate a first binarysignal when said digital value is below said control reference value,and to generate a second binary signal opposite to said first binarysignal when said digital signal exceeds said control reference value.15. A microprocessor as claimed in claim 3, wherein said controlcomparator is arranged to generate a first binary signal when saiddigital value is below said control reference value, and to generate asecond binary signal opposite to said first binary signal when saiddigital signal exceeds said control reference value.
 16. A system forcontrolling a device, including: a sensor for sensing a parameter ofsaid device; a microprocessor as claimed in claim 2, said microprocessorbeing connected with a control input to said sensor.
 17. A system forcontrolling a device, including: a sensor for sensing a parameter ofsaid device; a microprocessor as claimed in claim 3, said microprocessorbeing connected with a control input to said sensor.
 18. A system forcontrolling a device, including: a sensor for sensing a parameter ofsaid device; a microprocessor as claimed in claim 4, said microprocessorbeing connected with a control input to said sensor.